CVE-2026-26312 — Stalwart Mail Server has Out-of-Memory Denial of Service via Malformed Nested MIME Messages

Description (CNA)

Stalwart is a mail and collaboration server. A denial-of-service vulnerability exists in Stalwart Mail Server versions 0.13.0 through 0.15.4 where accessing a specially crafted email containing malformed nested `message/rfc822` MIME parts via IMAP or JMAP causes excessive CPU and memory consumption, potentially leading to an out-of-memory condition and server crash. The malformed structure causes the `mail-parser` crate to produce cyclical references in its parsed representation, which Stalwart then follows indefinitely. Version 0.15.5 contains a patch.

Affected (CNA)

Vendor / product	Versions
stalwartlabs / stalwart	affected >= 0.13.0, < 0.15.5

CWE

CWE-770

References

https://github.com/stalwartlabs/stalwart/security/advisories/GHSA-jm95-876q-c9gw

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.